Self-cleaning filter



SELF-CLEANING FILTER ATTORNEY.

c. P. GRIFFITH SELFHCLEANING FILTER 1 Filed Jupe 2o. 1958l l Il"ll dll"5 sheets-Sheet 2 INVENT Y.

ATTORNEY.

.l May 27, 1941. cyP. GRIFFITH SELF-'CLEANING FILTER Filed June 2o, 19385 Smets-sheets ATTORNEY.

May 27,1941- V c. P. GRIFFITH I 2,243,559 l l SELF-CLEANING FILTER FiledJune 2o, 193e 5 sheets-Skeet 4 llllllllllllllllll iIIIIIIIIIIIIIIIIIIIIQumr .grlglllmn May 27, 1941. c, P. 'GRIFFITH 2,243,559

SELF-CLEANING FILTER y Filed June 20, 1938 5 Sheets-:Sheet 5 VINVE R.

. ATTORNEY.

scrapers are individually held against Patented Mayl 27, 1941SELF-CLEANING FILTER# Clement P. Griffith, Fort Wayne, Ind., assigner toS. F. Bowser & Company, Incorporated, Fort Wayne, Ind., a corporation ofIndiana Application June 20, 1938, Serial No. 214,645

(Cl. 21o-184) Claims.

This -invention relates to self-cleaning lters or strainers and moreparticularly to filters or strainers employing elements which aremounted for rotation relative to stationary scraper blades which serveto remove accumulated cake," and in Whichthe scraping cycle is extendeduntil a predetermined pressure dirferential is attained.A

An object of the invention is .to provide automatic means for settingthe cleaning mechanism in motion when the back pressure rises to apredetermined magnitude.

A further o bject of the invention is to provide a lter or strainer fromwhich the lter elements can readily be removed and replaced.

Still another object of the invention is to provide -a novel strainerelement which comprises a wire, wound helically upon a cage and fastenedthereto.

A further object of the invention is to provide a compact elementdriving system.

Yet another object of the invention is to provide a novel scraper unitin which a plurality of the filtering element.

Another object of the invention is to provide a scraper unit having aplurality of Scrapers which are yieldably held against the lteringelement.

Still another object of the invention is to provide a. scraper unithaving a plurality of scrapers which are individually adjustable, towardor from the elements.

Another object of the invention is to provide a control circuit by meansof which the scraping Aoperation is interrupted by thermal control meansto prevent damage to apparatus in the circuit.

Yet another object of the invention is to provide a control circuit bymeans of which the scrapingcycle is intermittently interrupted andrestarted and then is finally interrupted.

A further object of the invention is to provide a control circuit bymeans of which the intermittent scraping action may be effectedcontinuously or in cycles initiated and terminated in accordance withthe pressures.

These and other objects will become apparent from a study of thespecification in connection with the accompanying drawings in which:

Figure 1 isv a perspective view of the exterior of the apparatus.

Figure 2 is a perspective view of the apparatus parts broken away toshow the lter elements, scrapers, drive mechanism and other parts inassembled relation in the shell. o

Figure 3 is a perspective exploded'view of the partsof Figune 2 removedfrom the shell.

Figure 4 is an elevation of one scraper blade in assembled relation onthe supporting shaft.'

Figure 5 is a section of. the mechanism of Figure 4taken on the line 5-5thereof.

Figure 6 is a diagrammatic view showing'the electrical control system.

vFigure 7 is a perspective View showing the reduction gearing.

` -Figune 8 is a partial plan View showing the details of the manifold.l

Figure 9 is a sectional dview taken on the line 9-9 of Figure 8 showingthe manifold and part of the inlet conduit.

I Figure 10 is a partial plan view of a ilter element with a portion cutaway to show the supporting structure.

Figure 11 is an elevation partially in section showing the winding ofthe lter element and the supporting structure.

Shell construction and. manifold The numeral II indicates a cylindricalshell which has integrally attached thereto a bottom head I3 on whichare xIed leg members I5 having foot pieces I1. Surrounding the upper endof the shell, a. ring I9 is attached for the purpose of retaining agasket (not shown) which is adapted to rest on the upper circular edgeof the shell.

An upper head 2l is removably mounted on the shell with its lowercircular edge resting upon the gasket and in alignment with the uppercicular edge of the shell. Thus, a seal is formed between the upper headand shell.

A clamping ring 23 is xedly attached to the head as by welding and isadapted to be engaged by clamping members 25 which are slidably mountedon clamping bolts 21 which are in turn pivoted on pins 29 set in pairsof lugs 3| mounted on the shell. By drawing down on the nuts mounted onthe clamping bolts, the upper head may be evenly and securely held onthe gasket.

An inlet opening 39 is formed in the shell II near its upper end and issurrounded by a boss 4I which is provided with suitably tapped holes sothat the flange of the inlet line may be readilyattached. Suitablecleanout and inspection openings 33 and 35 respectively, are provided inthe shell.

An outlet opening 43 is provided in the'shell II at its lower end and issurrounded by a boss-45 which is also provided with tapped holes so thatthe ange of the outlet line may be readily attached.

A conduit n Ie'ads from the opening, radiauy inwardly to the axis of theshell where it turns in place.

ninety degrees, upwardly as shown in Figure 3. The axis of theupwardly'extending portion 49 of the conduit is coaxial with the shelland is formed with a bell mouth 5| (see Figure 9). The interior of thebell is formed with a spherical seat portion' 53 which is adapted toreceive a spherical bearing 55 formed on the manifold 51.

In Figure 3. is shown a channel member 55 which has its ends fixed tothe shell I i and which extends under a projection 58 on the conduit 41and serves to support it and the weight oi' a'po'rtion of the apparatusmounted on it.

The spherical surface 55 is divided by a circular groove 59 whichreceives packing for sealing the joint.

Any inverted truncated cone 5I serves to join v the spherical bearingwith the header portion of the manifold which comprises a plurality'ofradially extending projections 53 which have upwardly facing openings 55therein which are adapted to receive the lower ends of the filteringelements as will be seen. 'Ihe interior of this manifold forms afiltrate chamber.

Each opening 55` is provided with a cylindrical bushing k51 and isadapted to receive the journaly 59 on the filter element (Figure 11) toprevent passage of liquid therebetween. The bushing is held in place bymeans of dowel pins 11.

A tapped boss 1| is provided in the manifold in axial alignment witheach of the openings 55 to receive a bolt which is ad'apted to hold asealing plate over the opening 55 in the event it is desired to omit thefiltering elements which would otherwise occupy the opening.

Eachof the projections 53 are provided with an outwardly extending boss13 which is permo'nted the hencauy wound nner wire Hs. The upper head I3is provided with a shaft 99 which, as described above, projects throughthe head 8|.

The lower head is provided with a journal 59 which is adapted to bereceived in the bearing 51 as described.

'Ihis lower head is provided with an axial opening helix having a pitchgreater than the diameter of the wire so that a helical opening will beleft between adjacent turns. In'the round wire construction, after theelement is wound, the wire is soldered to the cage so' as to maintainthe size of the filtering opening constant.

Reduction gearing A gear |2| is keyed on each of the shafts 99 above thesurface of head 8|. All of the gears lie vin a common plane but do notmesh with each other.

Mounted in openings in bosses |01 on the head (see- Figures 3 and 7) arecap screws |23 which are surrounded by spacers |25 which serve tosupport a gear supporting plate |25 in spaced relation with respect tosaid head.

An arm |21 (Figure 7) is formed integrally with plate |25 and supports aboss |29 in which forated to receive a combined space rod, tie-rod, andscraper shaft 15 which runs to the upper head later to be described.

Upper head construction The upper head .(Figure 3) indicated generallyby numeral 8| is a substantially fiat plate,

'ribbed for strength and provided at its edge with three bosses 83which'are perforated to receive the upwardly projecting stem 85 of aguide bracket 91 which is fixed to the inside of shell A nut threaded oneach stem holds the head Six radially outwardly directed bosses` 89 aredrilled and tapped to receive adjustable guide studs 9|, which afterbeing adjusted to the internal diameter of the shell are locked in placeby lock nuts.

Three equally spaced perforated bosses 93 similar to bosses 83 areprovided with eye-bolts -95 to facilitate the removal of the lteringmechanism from the shell.

Six perforated bosses 91 located at the base of bosses 89 are providedto receive the shafts 99 of the filter elements which projecttherethrough.

Six other equally spaced perforated bosses Filtering elementconstruction The ltering elements comprise a cage having heads ||3 and||5 and longitudinal ribs ||1 forming a series of bars upon which may beis carried a stud |33. A worm gear |35 and a spur gear |31 are formedintegrally and mounted on the stud with the worm gear uppermost.

A boss |39 is also supported by the arm |21 in parallel relation to boss|29 and shaft |4| is Journailed in the boss |39 and in the opening inthe central boss |43 of lthe head 9| (Figure 3).4 A ring gear |45 ismounted on a flange |41 of a gear |49 which is looselymounted on shaft|4| in meshing, relation with the gears |2| on the filter' elements. Thering gear meshes with the spur gear |31 described above and is adaptedto be driven thereby.

Two horizontally spaced bosses |5| are formed integrally with plate |26and serve to rotatably support a shaft |52 on one end of which ismounted a worm |53 which drives the worm wheel- |35. A worm wheel |54is-mounted to drive the shaft |52 and is adapted to be driven by a wormI 55 which is fixed to rotate with One-half of a coupling |51 isattached to the upper end of shaft |4| while the complementary half |59of the coupling is mounted on the lower end of a shaft |5| which is thearmature shaft of an electric motor |53.

Scraper assembly Fixed to each of the shafts 15 by means offset yforated to receive shaft 15. The blades aresharpened at the edge |19which bears against the lterlng unit. A spring |5| is received at oneend in seat I1| and its other end bears against the scraper blade.I Theblades are so mounted on'shafts 15 that they extend between the shaftsand the filter element uponv which they operate.

Motor control system In Figure 6, numerals L1 and L2 represent contactsleading to the power supply line while M1 and M2 represent contactswhich are connected to the motor |53 by lines |9| and 223 respectively.Contacts H1 and H2 are connected in a holding circuit which will bedescribed.

R1 and R2 represent the contacts of a thermal relay .which is controlledby a heating coil |89 in the line |9| which connects the motor withcontact M1. Contact R1 is connected with contact L1 by a line |83 whilecontact R2 is connected-with one side of coil i'l by line |93.

A switch |9|i comprising contacts |95, |97 and |99 which close contactsL1, M1; L2, M2; and H1, H2, respectively, is connected to be operated toits closed position when coil i8? which is connected in line |98 isenergized.

A line connects coil |8l with contact H1 and a line 203 connects H1 witha contact S1 of a selector switch indicated generally by numeral 205While a line 205 connects S1 with a'contact P1 of a pressure operatedswitch 205.

The other contact P2 of the pressure switch is connected by line 207 tothel other contact S2 of the selector switch 204 which in turn isconnected by line 209 to the contact H2.

Pressure switch 206 may be of any-suitabletype. As shown, it comprises adiaphragm 2|| which actuates a switch element P3 which is moved intoengagement ,withcontacts P1 and P2 as the pressure in the lter shellincreases beyond a -predetermined amount.

Selector switch 206 may also be of any suitable design. As shown, itcomprises pivotal contact elements Sa and S4 which may be moved into orout of engagement with the terminal S1 and' S2 respectively. Either oneor the other of the pairs of contacts are in engagement at'all times.

Both contacts S2 and S4 are connected by line 2|3 to terminal O1 of aresistor 2I5 and to a Operation Contaminated liquid such as lubricatingoil, etc.,'is pumped into the filter shell preferably under pressure.The liquid flows through the filter surfaces of the filtering elementsI'|| and lonpressure switch 208 will be connected by bar P3. If it isassumed that the selector switch 204 is set for automatic operation,contacts S2 and S4 wil-l be in engagement. Further, since no current hasbeen flowing in any of the circuits, contacts R1 and R2 will be closedas will contacts T1 and T2.

Upon closing of the pressure switch as noted above, a circuit will beset up including contact L2, line 2|9, contacts T2 and T1, Thermotector2N, terminal O1, line 2|3, contacts S4 and S2, line 20|, contacts P2, P3and P1, line 205, contact S1 and line 203 to contact H1, line 20|vthrough the magnet coil |8'| and by way of line contacts T1 and T2,Thermotector 2|?, termil nal 01 and line 2|3, contacts S4 and S2, line,200, contacts H2, |99 and H1, line 28|, coil itil, line |93, contactsR2 and R1, line |82 .to contact L1. Thus, control of coil |8`| isplacedin Thermotector 2|`| independently of the pressure switch. At thesame time, the closing of contacts L1. |95, M1 establishes a heatingcircuit through the resistorv 2|5 from contacts L1, |95, M1, line 22|,connections O2 and O1 to "Thermotector 2|l, contacts T1 and T2, line 2|9to contact L2.

The eil'ect of the coil |81 is such that only a small current will passthrough it, and this current is not sumcient to heat the Thermotector2|?. For this reason` the separate heating circuit just described isnecessary.

As Thermotector 2|l heats and reaches a predetermined temperature, thecontacts T1 and |63, the temperature of the heating coil |89 rises 1gitudinally thereof through the opening 66 and into the manifold 5lwhence it ows through conduit 4l to a suitable receptacle.

As the liquid passes through the filtering surfaces, dirt, chips, scaleand other impurities which are larger than the openings in the surfaceare caught and held while liquid and smaller particles pass through thesurface.

Eventually a cake will form on the filtering surface and as a result thepressure in the shell will build up and the eiiciency of the unit willbe reduced.

When the pressure in the shell reaches a predetermined amount, thecontacts P1 and P2 of T2 will separate and break the holding circuitthrough coil |81 and a spring 225 shown diagrammatically in Figure 6will move switch elements |95, |91 and |99' out of contact with theirasso-- ciated contacts and the motor will stop. However, if theoperation of the' motor has not been sufficient to reduce the pressurein shell to the required amount, the pressure switch 209 will still beclosed and as soon as the Thermotector 2| 'l cools, the contacts T1 andT2 will again engage and as a result the process will be repeated. Whenthe pressure is reduced sufficiently to cause switch 205 to open, theoperation of the motor will continue until the succeeding opening of thecontacts T1 and T2 whereupon the cycle will be completed. y

If, at any time during the operation of motor above a predeterminedmagnitude, the contacts -R1 and Rz will be separated to break thecircuit .through the coil |81 and this causes thel motor the motor willagain be started.

Should the selector switch 204 be set'for manual operation, the contactsS1 and Ss will be closed and contacts S2 and S4 will be opened. Thepressure switch is thus shunted and the motor will' be energized anddeenergized alternately solely under control `of the thermostaticswitchv set inla neutral'position with contacts Si and S4 out ofengagement with contacts Sz and Sa respectively, so that none of thecontrol circuits` can be established.

When the'motor |63 is energized shaft |6| is rotated counter-clockwisewhen looking toward the pulley end of the motor as shown by the arrow inFigure 3. The motion of shaft |4| is clockwise as viewed in Figure 7 andsince worm |55 has a left hand helix the shaft |52 will rotate clockwiseas shown in Figure '7. Worm |53 has a right hand helix and as a result,the worm wheel |35 and spur gear |31 are given a counter-clockwiserotation as viewed in Figure 7 and the gears |45 and |49 will besimilarly rotated so that the gears |2| on the elements will be drivenin the reverse direction which is clockwise. This advances the elementstoward the sharpened edges of the scraper blade (as will be seen inFigure 3) and the cake formed on the elements will be separatedtherefrom and will drop to the bottom of the shell where it may beremoved through the cleanout openings.

The reduction effected by the gear set (Figure '7) from shaft |4| toshaft 99 is from 1725 R. P. M. to 5.46 R. P. M. Worm |55 has two threadsor helices and worm gear |54 has 20 teeth providing a ten to onereduction so that the speed of gear |54 would be 172.5 R. P. M.

Similarly the second worm |53 has two threads or helices and worm gear|35 has twenty teeth giving a second ten to one reduction with theresult that gear |31 will rotate at 17.25 R. P. M. This gear has twentyteeth and its meshing ring gear |45 has sixty-nine teeth hence the ringgear and gear |49 which rotates with it will rotate at 17.25X20/69 or 5R. P. M.

However, since the gear |2| on the element has sixty-five teeth and thegear |49 has seventy-one teeth, there will be an increase in speed ofthe element in the amount of X71/65 or 5.46 R. P. M.

If, for any reason, it becomes necessary to remove the filteringmechanism, a mast may be attached to suitable pads on the shell andafter clamps 25 have been loosened and swung out of position, the cover2| may be removed. This is readily accomplished because the driveconnection 51|59 comprises merely any axially separable positive driveclutch.

After removing the head, the nuts may be retween said manifold and gsaidhead for scraping moved from supports 85 and the hoist chains may behooked in the eye-bolts 951 and the entire filtering mechanism may belifted up and out of the shell.

The pressure of the scraper Vblades 'may be ad ening the screws willserve to retain the hubs in adjusted position.

It is obvious that various alte y tions, may be made in the size, form,Varrangement and con- 2. In a filter comprising a casing having an,

inlet and an outlet, the sub-combination of a manifold forming a fluidchamber, means forming fluid passages including an outlet in saidmanifold, a head, a plurality of hollow filtering elements each providedwith a fiuid passage,

means mounting said elements for rotation be` tween said head andmanifold with the fluid passage of each element in communication with apassage in said manifold, means mounted bethe filtering surface of saidelement, means mounted on said head for rotating said element relativeto said scraping means, and means f or removably mounting saidsub-combination of elements as a unit in said casing with said manifold'and casing outlets in communication.

the exterior of said element comprising a shaft,-

mf ans mounting said velement and shaft for m yvement relative to eachother, means for fix-` ing said shaft against axial rotation, laplurality of scrapers mounted for free rotation on said shaft, yieldablemeans individual to each scraper for pressing said scrapers intoengagement with said element and means associated with each 'v scraperfor adjusting the pressure exerted by its individual yieldable means.

' 4. In a filter, the combination of a container having a liquid inletand a filtrate discharge conduit, the latter being formed with Iaspherical socket, a filtering mechanism comprising a head, a manifoldforming a filtrate receiving chamber and a plurality of filtering meanssupported by said head and manifold-and adapted to discharge ,into saidfiltrate chamber,V an outlet for sain chamber having a spherical seatadapted to engage said socket to form a liquid tight connection, saidfiltering mechanism being removable as a unit from said container bylifting it to disengage said seat and socket. v -5. In a filter, thecombination of a container having a liquid inlet and a filtratedischarge struction of parts without departing from the spirit of 'theinvention and for this reason applicant does not desire to be limitedsolely to the What I claim to be new and desire to protect 4by LettersPatent of the United States is.:

l. In a filter comprising a casing having an inlet and an outlet, thesub-combination of a manifold forming a fluid chamber. means formingfluid passages in said manifold. a head, a

conduit, the latter .being formed with a. spherical socket, a cover forthe container, power means mounted on-said cover and yconnected todriving means passing through said cover, a filtering mechanismcomprising a head, a manifold forming a filtrate receiving chamber,bearings formed in said head and manifold, filtering means ro-A tatablysupported in said bearings between said head and manifold and adapted todischarge into said filtrate chamber, gearing connecting said drivingmeans and said filtering means for ro- 'y tating thelatter, said drivingmeans and saidl gearing each supporting s. part of an axially'separablecoupling which is automatically disconnected upon lifting of the cover,an outlet for said chamber having a spherical seat adapted to engagesaid socket to form a liquidv tight connection, said filtering mechanism'being "removable as a unit from said container by lifting it todisengage said seat and socket after 'said cover has been removed.

6. In a filter comprising a casing having an inlet and an outlet, thesub-combination of a manifold forming a fiuid chamber, means formingfluid passages including an outlet in said manifold, a head, means formounting said head in. spaced relation with said manifold, a pluralityof hollow filtering elements each provided with a fluid passage at oneend, means mounting said elements for rotation between said head and,manifold with the fluid passage of" each element and oneof saidmanifold in communication, said mounting means including means forming aliquid tight connection between the manifold and element, and means forremovably mounting said subcombination of elements as a unit in saidcasing with said manifold and casing outlets in communication.

7. In a filter, the combination of a hollow cylin- Adrical lteringelement, means for scraping the of elements adjustably mounted on' saidshaft for individually adjusting the pressure exerted by each of saidyieldable means.

8. In a lter, the combination of a container, a removable cover forsaid-container, a. unitary filtering mechanism removably mounted in saidcontainer and -comprising a manifold, a head, bearings formed in saidmanifold and head, and filter-- ing means rotatably mounted in saidbearings and disposed between the manifold and said head, power meansmounted on said cover and separable power transmission means mounted onsaid head and cover for connecting said filtering means with said powermeans.

9. In a filter, the combination of a container having an inlet and anoutlet, a unitary filtering mechanism comprising a manifold having adischarge opening, a head, and filtering means disposed therebetween, asupport disposed in said container, a channel through said supportcommunicating with said outlet and a separable unia conduit incommunication with said vchannel and said opening.

10. In a filter, the combination of a container having an inlet and anoutlet, a unitary filtering mechanism comprising a manifold having adischarge opening, a head, and filtering means disposed therebetween, asupport disposed in said container, a channel through said supportcommunicating with said outlet and a separable universal connectionbetween said filteringmechanism and said support, said connection havinga condnit in communication with said channel and said opening, and meansin said container for locking said mechanism in placeA in said con-

